1. Field of the Invention
This invention relates generally to refrigerators, and specifically, to an improved ventilation system for an absorption refrigerator located within the interior of a vehicle.
2. Description of the Related Art
It is common for recreational vehicles to have refrigerators on board for cooling and preserving food and drinks in a compartment. These refrigerators are usually absorption-type refrigerators which use a heat source to effect refrigeration. An absorption refrigerator has a heat generator which heats a solution of a refrigerant and an absorbent. The heat releases the refrigerant from the absorbent to form a high pressure refrigerant vapor. The refrigerant vapor is condensed in a cooling condenser. Low pressure solution from the heat generator is sprayed on the refrigerant vapor in an absorber to absorb the vapor. The absorption causes the pressure of the vapor to be reduced, thereby causing evaporation in an evaporator between the condenser and the absorber. The refrigerant vapor expands in the evaporator which causes a temperature drop in the refrigerant which is used to cool the compartment. The solution of refrigerant and absorbent is then pumped back to the heat generator.
Absorption refrigerators are favored in vehicles, such as campers or recreational vehicles, because a compressor is not required and the heat generator can be an electrical resistance heater or a gas heater. The electrical resistance heater can be powered by a direct current supply of the vehicle or a commercial alternating current supply at a campground, for example. The gas heater can be fueled by propane gas which is usually carried on recreational vehicles. Combustion of the propane creates waste gasses, such as carbon dioxide, which should be vented outside the vehicle.
It is necessary to cool the condenser and absorber of the refrigerator. This is economically achieved by creating an airflow over the condenser and absorber. To create this airflow, the refrigerator is usually located adjacent an outer wall of the vehicle, and a duct is provided through the wall to permit airflow over the condenser and absorber. An exhaust is provided through a second duct. In some installations, a fan is provided to promote airflow. Such fans run continuously and are a significant drain on available power.
Locating the refrigerator near the outside wall limits the arrangement of other objects in the vehicle, such as cabinets, partitions, furniture and other appliances. In addition, panels for access to the refrigerator located on sidewalls of the vehicle can permit rain water to enter the vehicle or the refrigerator.
U.S. Pat. No. 4,545,211 to Gaus shows a compressor-type refrigerator for a vehicle. The refrigerator is located in an "island" in the vehicle between the passenger seats. An air intake is provided on the front of the island and an air outlet is provided on the back. A fan draws air from the vehicle through the inlet, over the condenser, and through the outlet back into the vehicle.
It would be desirable to provide a refrigerator having a ventilation system which permits an absorption-type refrigerator to be placed at an interior location in the vehicle. The need for air intake ducts in the sidewalls should be eliminated to provide floorplan flexibility. Airflow over the condenser and absorber should be facilitated by the ventilation system while conserving power. Air used to cool the condenser and absorber should come from outside the vehicle and be exhausted to carry heat and combustion products outside the vehicle.